Expected ')' in regular expression

You attempted to create a regular expression sub expression, but did not include the closing parenthesis ")". Parentheses have several purposes in regular expressions. Primarily, they group separate items into a single sub expression, so that the items can be treated as a single unit by *, +, ?, and so on.

To correct this error

Add the right (closing) parenthesis ")" to your regular expression sub expression.

See Also

Regular Expression (RegExp) Object